Annealing box



May 23, 1933. w. J. KELLY El AL ANNEALING BOX Filed July 6, 1952 2 Sheefs-Sheet. l

INVENTOES War/fen! /\e// Alf/for? P Burns ATTORN EYS Patented May 23, 1933 UNITED STATES PATENT OFFICE j WALTER J'. KELLY AND MILTON P. BUR-NS, F FAIRFIELD, ALABAMA ANNEALIN G BOX Application filed July 6, 1932. Serial No. 621,116.

This invention relates to improvements in annealing boxes and aims to provide a box of this character having a roof which is strengthened by interior reinforcing ribs having ducts formed therein for the circulation of atmospheric air. While not limited thereto, the box embodying our invention is particularly useful in the manufacture of rolled metal sheets. In the usual use of annealing boxes used for manufacturing sheets, the box is pulled out of an annealing oven and permitted to cool in the open air. During such cooling, the outside of the box cools first. This has caused certain difiiculties in the boxes heretofore used. It is broadly old to use boxes with arched roofs and also such arched roofs with interior reinforcing ribs. But, such prior boxes have been unsatisfactory. We have determined that the ribs of the boxes heretofore used for reinforcing the roof instead of serving their intended purpose have in fact contributed to the failure of the roof and we have determined in practice that the ribs of annealing boxes heretofore used have a tendency to cause the roof to sag and spread.

It is our belief that the reason for this is that when the box is removed from the oven in a red hot state, the outside of the box is the first part to be cooled and with particular reference to the roof the outside thereof is the first part of the roof to cool and shrink while the bracing ribs on the inside of the box are still in a red hot and thus expanded condition. Assuming the ribs as acting as beams, such beams will have their upper most fibres shrinking and their lowermost fibres red hot. The resulting stresses thus tend to stretch the lower fibres of the rib, which being red hot yield to a limited ex tent and then gradually cool oil" in this stretched condition. Similarly, when the annealing box is placed in an annealing oven the tendency is to first expand the top fibres of the bracing ribs and to tend to compress the lower fibres of said ribs. But, in this instance, the lower ribs are relatively cold and will not yield to the compressing strains. Thus, in the cycle of alternately cooling and heating the conventional types of annealing boxes heretofore used the lower fibres of the bracing ribs are stretched on each cooling thereof and the roof of the box consequently sags and spreads. In time, such sagging or spreading ultimately destroys the usefullness of the box and it must be discarded or scrapped.

To overcome the difliculties, we will provide a box whichhas a materially longer-useful life than the boxes heretofore available and weprovidemeans permitting a circulating of external air through the interior horizontal ribs so'as to lessen the strainswhich are set up due to temperature variations. Our improved construction also has the advantage that it permits the provision of an annealing box with an arched roof having a a smaller rise than designs of annealing boxes heretofore used. This results in a smaller insulating air space at the top of the box through which the heat must pass from the roof to the sheets placed in the box during the annealing operation. Because of this decreased insulating air space at the top of the box, the same is more efiicient than annealing boxes heretofore used having roofs with arches having a comparatively greater rise. The increased efficiency secured by .an annealing box according to our invention which is due to the relatively small space at the top of the box contributes an operating advantage because a given annealing job can be accomplished in less time than was heretofore required for the same work. p

The above and other features of the inven tion will be fully apparent from the following description when read in connection with the accompanying drawings.

In the drawings i Fig. l'is a view partlyinplan and partly in horizontal section in different planes;

. Fig. 2 is a side elevation of Fig. 1 with an intermediate partbroken away and the right hand side shown in central longitudinal section; i

Fig. 3 is a transverse of Fig. 2;

Referring in detail to the drawings, 5 represents the box as a whole, which includes two side walls 6, twoend walls 8 and the roof 10.

section on line 33 The sides and roof are stiffened by outwardly projecting corrugated portions, indicated at 12. The sides and ends are stiffened by outer ribs 14 and 16, the former being substantially horizontally disposed and the latter being angularly disposed. Upright reinforcements 18 are provided in the side walls in the spaces between the corrugations 12, and similar reinforcements 20 are provided in end walls- These reinforcements, as shown, are provided with chambers or ducts '19 adapted to permit the free circulation of cooling air. The 'diagonal ribs 16 bridge the spaces between corrugations 12 and the outer reinforcements 18. To facilitate the handling of the box by means of an overhead crane and other suitable lifting means, I provide four lugs 22, two beingpositione-d on eachside of the box, atpoints spaced a short distance below the roof line. Locatedion the interior of the box and depending downwardly therefrom, there are a plurality of transversely extending reinforcing ribs 24. These have openings 26 therein immediately below the arched roof of the box so as-to permit the free passage of air or gases within the box through the several chambers 28 formed between adjacent ribs 24.

At the lower extremity of each reinforcing rib 24, there is an enlargement 25 which forms an enclosure for a duct 30. The several ducts 30 formed in-the reinforcing ribs-provide passages for the circulation of air while the box is cooling off. Similarly, these ducts provide a-path for the entrance of heat gases while the box is being heated. As thus arranged, it is clear that the ducts '30 are isolated from the atmosphere within the box, but are freely open to the atmosphere outside the box. The cooling'ducts in the interior reinforcing ribs provide means whereby the stresses set up during the alternate heating and cooling of the box, are substantially equalized. This greatly increases the useful life of'the box, as compared to boxes heretofore used, which do not employ reinforcing ribs having such ducts.

Having thus described our invention what we desire to secure by Letters Patent arethe improved features of annealing box construction as defined in the following claims,.these claims to be construed as broadly as is consistent with the teachings of the prior art.

What we claim is i 1. An annealing box of the character described having an arched roof' interior strengthening ribs for-med with ducts arranged to permit the circulation of external air to facilitate the equalization of stresses in said ribs due to temperature variations.

2. An annealingbox of the character described having an arched roof and strengthening ribs spanning the space immediately below the roof and having air cooling ducts therein, which are open to the atmosphere exterior to the box.

3. An annealing box of the character described having side and end walls and closed at the top by an arched roof and reinforcing ribs inside the box depending from said roof and having open ended transverse air ducts therein.

4. An annealing box of the character described having side and end walls and closed at the top by an arched roof and reinforcing ribs extending transversely below the roof and having ducts isolated from the atmosphere within the box but open to the atmosphere exterior thereto.

5. An annealing box of the character described having an arched roof and strengthening ribs spanning the space immediately below the roof, the lower extremities of said ribs being .enlarged and having ducts extending therethrough, which are open-to the at mosphere exterior to the box.

In witness whereof, we have hereunto signed our names.

lNALTER J. KELLY.

- MILTON'P. BURNS. 

